Increased phosphorylation of c-Jun NH (2)-terminal protein kinase in the sciatic nerves of Lewis rats with experimental autoimmune neuritis

The phosphorylation of c-Jun NH (2)-terminal protein kinase (JNK), one of the mitogen-activated protein kinases, was analyzed in the sciatic nerves of Lewis rats with experimental autoimmune neuritis (EAN). Western blot analysis showed that the expression levels of both phosphorylated JNK1 (p-JNK1, approximately 46 kDa) and phosphorylated JNK2 (p-JNK2, approximately 54 kDa) in the sciatic nerves of rats with EAN increased significantly (p < 0.05) at day 14 post-immunization (PI) and remained at this level at days 24 and 30 PI, with a slight decrease. In EAN-affected sciatic nerves, there was intense immunostaining for p-JNK in the infiltrating inflammatory cells (especially ED1-positive macrophages) and Schwann cells on days 14-24 PI, compared with those of controls. Some macrophages with increased p-JNK immunoreactivity was shown to be apoptotic, while some Schwann cells remained survived in this rat EAN model, suggesting that JNK is differentially involved in the EAN-affected sciatic nerves. These findings suggest that JNK phosphorylation is closely associated with the clearance of inflammatory cells as well as the activation of Schwann cells in the EAN affected sciatic nerves

Immunohistochemical study of osteopontin in boar testis

The expression of osteopontin (OPN) in boar testis was studied. Western blot analysis detected 66- and 32-kDa OPN immunopositive bands in the testes of adult boars. In postnatal piglets, the 66-kDa OPN band was detected in the testes, but not the 32-kDa band. In the newborn testis, OPN immunostaining was seen in gonocytes and in some supporting cells in the seminiferous tubules, as well as in interstitial Leydig cells. In the adult boar testis, OPN immunoreactivity was detected in seminiferous tubules with varying intensities. Intense OPN immunostaining was seen in the residual bodies and acrosomes in the spermatids while, occasionally, OPN immunostaining was seen in spermatogonia and various stage of spermatocytes but in few Sertoli cells in the seminiferous tubules. In addition, Leydig cells in adult boars were weakly immunostained with OPN. These findings suggest that OPN is detected in the majority of germ cells and is involved in spermatogenesis in boar testis

Gamma-ray irradiation stimulates the expression of caveolin-1 and GFAP in rat spinal cord: a study of immunoblot and immunohistochemistry

We studied the expression of caveolin-1 in the spinal cords of rats using 60Co γ-ray irradiation (single dose of 8 Gray (Gy)) in order to determine the possible involvement of caveolin-1 in the tissues of the central nervous system after irradiation. Spinal cords sampled at days 1, 4, and 9 post-irradiation (PI) (n = 5 per each time point) were analyzed by Western blot and immunohistochemistry. Western blot analysis showed that the expression of caveolin-1 was significantly increased at day 1 PI (p < 0.05), and returned to the level of normal control rats on days 4 and 9 PI. Immunohistochemistry showed that caveolin-1 immunoreactivity was enhanced in some glial cells, vascular endothelial cells, and neurons in the spinal cords. The increased expression of glial fibrillary acidic protein (GFAP), a marker for an astroglial reaction, was consistent with that of caveolin-1. In addition, caveolin-1 was co-localized in hypertrophied GFAP-positive astrocytes. Taking all these facts into consideration, we postulate that irradiation induces the increased expression of caveolin-1 in cells of the central nervous system, and that its increased expression in astrocytes may contribute to hypertrophy of astrocytes in the spinal cord after irradiation. The precise role of caveolin-1 in the spinal cords should be studied further

The expression and cellular localization of phospholipase D isozymes in the developing mouse testis

To examine the involvement of phospholipase D (PLD) isozymes in postnatal testis development, the expression of PLD1 and PLD2 was examined in the mouse testis at postnatal weeks 1, 2, 4, and 8 using Western blot analysis and immunohistochemistry. The expression of both PLD1 and PLD2 increased gradually with development from postnatal week 1 to 8. Immunohistochemically, PLD immunoreactivity was detected in some germ cells in the testis and interstitial Leydig cells at postnatal week 1. PLD was mainly detected in the spermatocytes and residual bodies of spermatids in the testis after 8 weeks after birth. The intense immunostaining of PLD in Leydig cells remained unchanged by postnatal week 8. These findings suggest that PLD isozymes are involved in the spermatogenesis of the mouse testis

Cytotoxicity of gamma-ray in rat immature hippocampal neurons

This in vitro study evaluated the detrimental effect of acute gamma (γ)-irradiation on rat immature hippocampal neurons. Rat immature hippocampal neurons (0.5 day in vitro) were irradiated with 0~4 Gy γ-rays. Cytotoxicity was analyzed using a lactate dehydrogenase release assay at 24 h after γ-irradiation. Radiation-induced cytotoxicity in immature hippocampal neurons increased in a dose-dependent manner. Pre-treatments of pro-apoptotic caspase inhibitors and anti-oxidative substances significantly blocked γ-irradiation-induced cytotoxicity in immature hippocampal neurons. The results suggest that the caspase-dependent cytotoxicity of γ-rays in immature hippocampal cultured neurons may be caused by oxidative stress